import logging
import json
import re

from contextlib import asynccontextmanager
from fastapi import FastAPI, HTTPException, Response, BackgroundTasks
from fastapi.responses import HTMLResponse, FileResponse, PlainTextResponse
from telegram_client import TelegramClient
from config import get_settings
import mimetypes
import os
from pyrogram import errors
from feedgen.feed import FeedGenerator

logger = logging.getLogger(__name__)
client = TelegramClient()
settings = get_settings()

@asynccontextmanager
async def lifespan(_: FastAPI):
    # Startup
    await client.start()
    yield
    # Shutdown
    await client.stop()

app = FastAPI(
    title="PyroTg Bridge",
    lifespan=lifespan
)

if __name__ == "__main__":
    import uvicorn
    uvicorn.run( "api_server:app", host=settings["api_host"], port=settings["api_port"], reload=False)

@app.get("/html/{channel}/{post_id}", response_class=HTMLResponse)
async def get_post_html(channel: str, post_id: int):
    try:
        post = await client.get_post(channel, post_id)
        if post.get("error"):
            raise HTTPException(
                status_code=404,
                detail=post["details"]
            )
        if "error" in post:
            raise HTTPException(status_code=404, detail=post["details"])
        return post["html"]
    except Exception as e:
        logger.error(f"HTML endpoint error: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e)) from e

@app.get("/json/{channel}/{post_id}")
async def get_post(channel: str, post_id: int):
    try:
        data = await client.get_post(channel, post_id)
        if data.get("error"):
            raise HTTPException(
                status_code=404,
                detail=data
            )
        return Response(
            content=json.dumps(data),
            media_type="application/json"
        )
    except Exception as e:
        logger.error(f"API error: {str(e)}")
        raise HTTPException(
            status_code=404,
            detail={
                "error": "post_retrieval_error",
                "message": str(e)
            }
        ) from e

@app.get("/status")
async def health_check():
    return {
        "status": "ok",
        "connected": client.client.is_connected
    }

@app.get("/media/{file_id}")
async def get_media(
    file_id: str,
    background_tasks: BackgroundTasks,
    response: Response
):
    try:
        file_path = await client.download_media_file(file_id)
        
        # Additional safety checks
        if not os.path.exists(file_path):
            raise HTTPException(status_code=404, detail="Temporary file not found")
        
        # Determine media type from file extension
        media_type, _ = mimetypes.guess_type(file_path)
        if not media_type:
            media_type = "application/octet-stream"
        
        # Add cleanup task
        background_tasks.add_task(lambda: os.remove(file_path) if os.path.exists(file_path) else None)
        
        return FileResponse(
            path=file_path,
            media_type=media_type,
            headers={
                "Content-Disposition": f"inline; filename={os.path.basename(file_path)}"
            }
        )
        
    except HTTPException:
        # Пробрасываем уже сформированные HTTPException как есть
        raise
    except errors.RPCError as e:
        logger.error(f"Media request RPC error {file_id}: {type(e).__name__} - {str(e)}")
        raise HTTPException(status_code=404, detail="File not found in Telegram")
    except Exception as e:
        logger.error(f"Media request failed {file_id}: {type(e).__name__} - {str(e)}")
        raise HTTPException(
            status_code=500, 
            detail=f"Internal server error: {str(e)}"
        ) 

@app.get("/rss/{channel}", response_class=PlainTextResponse)
async def get_rss_feed(channel: str):
    try:
        # Get last 20 posts
        posts = await client.get_channel_posts(channel, limit=20)
        
        # Create FeedGenerator
        fg = FeedGenerator()
        fg.title(channel)
        fg.link(href=f"{settings['pyrogram_bridge_url']}/html/{channel}", rel='alternate')
        fg.description(f'Telegram channel {channel} RSS feed')
        fg.language('ru-ru')
        
        # Add channel metadata
        fg.id(f"{settings['pyrogram_bridge_url']}/rss/{channel}")
        fg.link(href=f"{settings['pyrogram_bridge_url']}/rss/{channel}", rel='self', type='application/rss+xml')
        
        # Add posts
        for post in posts:
            fe = fg.add_entry()
            fe.id(f"{settings['pyrogram_bridge_url']}/html/{channel}/{post['id']}")
            fe.title(post['title'])
            fe.link(href=f"{settings['pyrogram_bridge_url']}/html/{channel}/{post['id']}")
            fe.pubDate(post['date'].astimezone(tz=None))
            fe.description(post['html'])
            fe.content(content=post['html'], type='CDATA')
            
            # Add media enclosures
            for media in post.get('media', []):
                if media.get('url'):
                    fe.enclosure(
                        url=f"{settings['pyrogram_bridge_url']}/media/{media['url']}",
                        type=media.get('type', 'image/jpeg'),
                        length=str(media.get('size', 0))
                    )
        
        # Generate RSS
        rss = fg.rss_str(pretty=True)
        return Response(content=rss, media_type="application/xml")

    except Exception as e:
        logger.error(f"RSS generation error: {str(e)}")
        raise HTTPException(status_code=500, detail="RSS feed generation failed")